Performance Improvement of Dye-Sensitized Solar Cells Using Room-Temperature-Synthesized Hierarchical TiO2Honeycomb Nanostructures

Highly ordered hierarchical TiO2nanostructures involving primary honeycomb and secondary nanoparticles and nanowires are prepared by a two-step facile process. The TiO2nanotube arrays grow first on Ti foil through anodization. After the wet-chemical reaction of the TiO2nanotube arrays with alkaline and acid solution in turn, the hierarchical nanostructures wire-in-honeycomb and porous honeycomb are obtained by a dissolution–coagulation and dissolution–adsorption mechanism, respectively. The power conversion efficiency of the hierarchical TiO2honeycomb nanostructures for the dye-sensitized solar cells (DSCs) shows a significant improvement, as high as 5.73%, increased by 1.42 times compared with that of TiO2nanotube arrays. The performance improvement of DSCs based on the hierarchical nanostructures is attributed to the increase in the specific surface area.